1. Department of Cardiovascular Surgery, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan
2. Department of Cardiovascular Surgery, Sapporo Cardio Vascular Clinic, Sapporo, Hokkaido, Japan
3. Department of Cardiovascular Surgery, Hokkaido Ohno Memorial Hospital, Sapporo, Hokkaido, Japan
4. Department of Neural Regenerative Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan